2026 ICD-10-CM Diagnosis Code F91.9Conduct disorder, unspecified

ICD-10-CM Codes›F01–F99›F90-F98›F91

ICD-10-CM F91.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

F91.9 is a billable ICD-10-CM diagnosis code for conduct disorder, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Disruptive, impulse-control and conduct disorders.

Code Identity

ICD-10-CM Code
F91.9
Billable Status
Yes — Valid for Submission
Code Describes
Conduct disorder, unspecified
Short Description
Conduct disorder, unspecified
Same as the full description in the CMS dataset.
Parent Code
F91
Conduct disorders

Code Classification

ChapterF01–F99Mental and behavioural disorders
SectionF90-F98Behavioral and emotional disorders with onset usually occurring in childhood and adolescence
CategoryF91Conduct disorders
This CodeF91.9Conduct disorder, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal behavior
  • Behavior problem of childhood and adolescence
  • Behavioral disability
  • Clark Baraitser syndrome
  • Conduct disorder
  • Conduct disorder in remission
  • Disruptive behavior
  • Disruptive behavior disorder
  • Intellectual disability, macrocephaly, hypotonia, behavioral abnormalities syndrome
  • Micrognathia, recurrent infections, behavioral abnormalities, mild intellectual disability syndrome
  • Mixed behavior and emotional disorder
  • Problem behavior
  • Problem behavior in adult
  • Ran away
  • Self destructive behavior
  • WAC-related facial dysmorphism, developmental delay, behavioral abnormalities syndrome
  • X-linked epilepsy with learning disability and behavior disorder syndrome

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Behavioral disorder NOS
  • Conduct disorder NOS
  • Disruptive behavior disorder NOS
  • Disruptive disorder NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Disorder(of)
      • conduct (childhood)
    • Disorder(of)
      • disruptive
    • Disturbance(s)
      • conduct
    • Disturbance(s)
      • conduct
        • disruptive

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MBD008
Disruptive, impulse-control and conduct disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Conduct Disorder

    a repetitive and persistent pattern of behavior in which the basic rights of others or major age-appropriate societal norms or rules are violated. these behaviors include aggressive conduct that causes or threatens physical harm to other people or animals, nonaggressive conduct that causes property loss or damage, deceitfulness or theft, and serious violations of rules. the onset is before age 18. (from dsm-iv, 1994)

  • Problem Behavior

    troublesome or disruptive behavioral displays.

  • Socialized Conduct Disorder

    a subtype of conduct disorder in which the affected child displays antisocial behavior despite still being able to make friends.

  • Undersocialized Conduct Disorder, Aggressive Type

    a subtype of conduct disorder in which the affected child displays aggressive, antisocial behavior and a lack of close friendships.

  • Conduct Disorder

    a disorder diagnosed in childhood or adolescence age group characterized by aggressive behavior, deceitfulness, destruction of property or violation of rules that is persistent and repetitive, and within a one year period.

Patient EducationClinical

Child Behavior Disorders

All kids misbehave some times. And some may have temporary behavior problems due to stress. For example, the birth of a sibling, a divorce, or a death in the family may cause a child to act out. Behavior disorders are more serious. They involve a pattern of hostile, aggressive, or disruptive behaviors for more than 6 months.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert F91.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
312.9 Conduct disturbance NOS
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About F91.9Overview

Is F91.9 (Conduct disorders) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report conduct disorder, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of F91.9?

Under the General Equivalence Mappings, conduct disorder, unspecified converts to ICD-9-CM 312.9 (conduct disturbance NOS). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.